The widespread adoption of cloud computing has introduced a paradigm shift in how organizations operate, offering enhanced scalability, flexibility, and cost-efficiency. However, the reliance on cloud services has also attracted sophisticated cyber threats, particularly Distributed Denial of Service (DDoS) attacks, which pose significant risks to both scientific research and commercial applications. This study conducts a comparative analysis of network performance under DDoS attacks within cloud environments, aiming to dissect the efficacy of existing mitigation strategies and to underscore the different impacts on scientific versus commercial cloud services. Through a combination of literature review, simulation of real-world attack scenarios, and comprehensive performance metric analysis, this research elucidates the evolving landscape of DDoS threats and advances in mitigation technologies, providing critical insights for enhancing cloud security.